1. Field of the Invention
The invention relates to a device and a method for repeatedly updating the function of a liquid quid crystal (LCD) monitor, and more particularly to a device and a method for repeatedly updating the function of a LCD monitor by using Display Data Channel (DDC) signal lines for signal transmission.
2. Description of the Related Art
In a current monitor system, particularly to a LCD monitor, a monitor controller must be exchanged when function modifying or debugging, resulting in high cost consumed. As to a further advanced monitor system, a corresponding monitor controller has a build-in read only memory (ROM) which is an erasable programmable read only memory. By updating data stored in the erasable programmable read only memory, function modification and debugging can be achieved.
Referring to FIG. 1, a conventional programmable LCD monitor with the circuit block diagram is shown. The conventional LCD monitor has a total of 18 VGA signal lines electrically coupled to a VGA card, which includes a vertical synchronous signal (Vsync) line, a horizontal synchronous signal (Hsync) line, a serial data (SDA) line, a serial clock (SCL) line, a ground (Gnd) line, a red (R) line, a green (G) line and a blue (B) line. During a normal operation, the LCD monitor controller 10 receives the VGA signals. The LCD monitor also coupled to a jumper 14 for connection to the flash ROM 20 or the erase/record socket 80. The flash ROM 20 stores the data used to control the displaying function. In addition, the LCD monitor 10 also has a panel connector to connect to the LCD displaying panel (not shown). Usually, the monitor controller 10 controls the display panel (not shown) based on the VGA signals. The Hsync, Vsync, SDA, SCL and R.G.B signal lines are electrically coupled to the monitor controller 10 for driving the scan and data signals to the LCD displaying panel.
When it is necessary to modify the function of the monitor system, data stored in the flash ROM 20 needs to be updated. First, the case of the monitor must be opened. Then, the first jumper 14 is used to separate the original circuit and the rewriting pathway to the flash ROM. And then, a cable connected to the socket 80 to transmit the updated data.
FIG. 2 is a schematic view showing the connection of a conventional LCD monitor system with a memory erase/record system. After the external casing of the monitor 100 is open, a main circuit board 110 is revealed. An erase/record socket 80 and a set of VGA signal lines 18 are laid on the circuit board 110. The first jumper 14 is found within a jumper area 22. The memory erase/record system 90 includes a ROM writer 92, a computer system 94 and a programming monitor 96. The computer system 94 controls all the operations of the ROM writer 92. Programming status of the operation can be observed through the programming monitor 96. When the ROM writer is plugged into the erase/record socket 80 of the main circuit board 110, memory inside the monitor can be reprogrammed by the computer 94 so that a different monitor function can be used.
Obviously, it is really inconvenient to update the monitor system because the case of the conventional monitor must be first opened, and then the jumper has to be switched for recording the erasable programmable read only memory of the monitor controller 10.
As a result, it is rather inconvenience when the monitor system, such as LCD monitor, is updated because it is necessary to open the case of the monitor and to switch jumpers for recording the erasable programmable read only memory of the monitor controller 10.
The invention is to provides a device for reprogramming function of a LCD monitor, which needs not to open the case and needs no the conventional jumper. Also and, it is not necessary to include a connector with pre-designed layout for isolating the previously original circuit and the rewriting pathway to the flash memory. The displaying function of the LCD monitor can be repeatedly updated and the information about on-screen display.
The present invention provides a LCD monitor control system capable of reprogramming monitor function. The monitor control system utilizes the VGA signal lines for transmitting signals during normal operation. The same VGA signal lines are also used for transmitting erase/record commands to the monitor system and to erase/record data into an external erasable programmable ROM.
The invention provides a device for reprogramming function of a LCD monitor, which includes a set of video graphic adapter (VGA) signal lines for transmitting a plurality of erase/record commands and a plurality of erase/record data. A signal detector is coupled to the VGA signal lines for detecting and re-transmitting the erase/record commands and data. An activation device is coupled to the signal detector, wherein the activation device is normally connected to a video pathway, but as soon as erase/record commands are detected, the activation device is switched to an erase/record pathway so that erase/record commands and data can be re-directed. A read-only-memory (ROM) erase/record command decoder is coupled to the activation device via the erase/record pathway, wherein the decoder translates the erase/record commands into a plurality of erase/read/write signals and translates the erase/record data into a plurality of address signals and a plurality of data signals. A plurality of address signals, a plurality of data signals and a plurality of control signals are coupled to the ROM erase/record command decoder. Consequently, data stored in the external ROM unit can be modified, according to the address, data and erase/read/write signals coming from the command decoder. A mode return device is coupled to the ROM erase/record command decoder and the activation device. Wherein, the reprogramming status of the ROM unit can be determined from the address, data and read/write signals so that the activation device can be triggered to switch over connection from the erase/record pathway to the video pathway as soon as reprogramming is finished.
In the foregoing device, the signal detector further includes an inter-integrated circuit multiple address content comparator circuit, which is coupled to the VGA signal lines for comparing with a plurality of consecutive address sequences in the erase/record data such that a set signal is transmitted when there is a match with a pre-set address sequence. A monitor-in-system programming control flag unit is coupled to the inter-integrated circuit multiple address content comparator circuit for transmitting a start signal after receiving the set signal.
In the foregoing device, the activation device further includes a monitor-in-system reprogramming initialization circuit for producing a select signal after receiving the start signal, as well as an erase/record pathway isolator for switching over connection from the video pathway to the erase/record pathway after receiving the select signal and transmitting the erase/record commands and data via the erase/record pathway.
In the foregoing device, the ROM erase/record command decoder further includes an inter-integrated interface circuit for receiving and translating the erase/record commands and data, as well as an erase/record command decoder for receiving translated erase/record commands and data and outputting address, data and erase/read/write signals.
In the foregoing device, the erase/record command decoder further includes a hidden ROM for holding a program code for erase/record commands; a random access memory (RAM) unit for holding erase/record data; a central processing unit coupled to the hidden ROM, the RAM unit and the inter-integrated interface circuit. Wherein the central processing unit receives the erase/record commands and data passing through the inter-integrated circuit interface circuit and then stores the erase/record data in the RAM unit, while the erase/record commands are decoded by referring to the program code in the hidden ROM and then the decoded commands are re-transmitted. An erase/record control register coupled to the central processing unit for receiving the decoded erase/record commands and converting the erase/record commands into the interface control signals or erase/read/write signals, and converting the erase/record data stored in the RAM unit into address and data signals.
The invention further provides a system for reprogramming the function of a liquid crystal display (LCD) monitor, which comprises an erase/record device for holding and transmitting a plurality of erase/record commands and a plurality of erase/record data. A set of video graphic adapter (VGA) signal lines coupled to the erase/record device for transmitting the erase/record commands and data. And, a LCD monitor controller with a monitor-in-system programming function, wherein the LCD monitor controller is coupled to the VGA signal lines so that the erase/record commands of the erase/record device and data are received from the erase/record device via the VGA signal lines, and then a plurality of address signals, a plurality of data signals, and a plurality of control signals are exported for reprogramming a ROM unit, wherein the ROM unit coupled to the LCD monitor controller via signal lines for transferring the address signals, the data signals and the control signals, so that data stored in the ROM unit can be modified according to the address signals and the control signals, and the data signals coming from the LCD monitor controller.
In the forgoing invention, the LCD monitor controller with monitor-in-system programming function includes a signal detector coupled to the VGA signal lines for detecting and transmitting the erase/record commands and data. An activation device is coupled to the signal detector. Wherein the activation device is normally connected to a video pathway, but as soon as erase/record commands is detected, the activation device is switched to an erase/record pathway so that erase/record commands and data can be re-directed. A ROM erase/record command decoder is coupled to the activation device via the erase/record pathway, wherein the decoder translates the erase/record commands into a plurality of erase/read/write signals and translates the erase/record data into a plurality of address signals and a plurality of data. A mode return device is coupled to the ROM erase/record command decoder and the activation device. Wherein, the reprogramming status of the ROM unit can be determined from the address, data and erase/read/write signals so that the activation device can be triggered to switch over connection from the erase/record pathway to the video pathway as soon as reprogramming is finished.
The invention also provides a method for reprogramming the function of a LCD monitor system. The method includes tapping a plurality of signals from a set of video graphic adapter (VGA) signal lines to perform a plurality of consecutive address sequence comparisons with a pre-set address sequence. A programming mode inside the LCD monitor system is triggered when one of the tapped consecutive address sequences matches that of the pre-set address sequence. An erase/record command is read and it is decided what actions to take as soon as the programming mode is activated. The erase/record data is read and the erase/record data is written into a memory unit when the erase/record command is for a write operation, and then returning to the previous step. When the erase/record command demands a return to a non-programming mode, the process returns back to the very first step.